scholarly journals Effects of tree sapling diversity and nutrient addition on herb-layer invasibility in communities of subtropical species

2012 ◽  
Vol 02 (01) ◽  
pp. 1-11 ◽  
Author(s):  
Sabine Both ◽  
Teng Fang ◽  
Martin Baruffol ◽  
Bernhard Schmid ◽  
Helge Bruelheide ◽  
...  
Keyword(s):  
Nutrient Addition ◽  
Herb Layer ◽  
Subtropical Species ◽  
Tree Sapling

The problem of the primary reduction of species in the analysis of general geobotanical tables and the elaboration of analytic programs

2001 ◽  
pp. 99-106 ◽  
Author(s):  
Yu. N. Neshatayev
Keyword(s):  
Vegetation Classification ◽  
Sample Plot ◽  
Herb Layer ◽  
Huge Amount ◽  
Species List ◽  
Community Types ◽  
Primary Reduction

If one processes a huge amount of data when es­tabli­shing the vegetation classification, it appears necessary to use the uniform algorithms of analysis. Such goals as distinguishing the reliable community types (associations or other syntaxa) involve the operational reduction of either the species list, or (more seldom) the sample plot set. This is especially useful for the analysis of multi­specific communities of meadows, steppes, or another types of markedly continuous polydominant vegetation with «fuzzy» structure of the herb layer.

The effects of tree cover and soil nutrient addition on native herbaceous richness in a neotropical savanna

Biotropica ◽  
2021 ◽  
Author(s):  
Klécia Gili Massi ◽  
Chesterton Ulysses Orlando Eugênio ◽  
Augusto César Franco ◽  
William A. Hoffmann
Keyword(s):  
Soil Nutrient ◽  
Nutrient Addition ◽  
Tree Cover ◽  
Neotropical Savanna

scholarly journals Effect of thinning intensity on understory herbaceous diversity and biomass in mixed coniferous and broad-leaved forests of Changbai Mountain

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Gerong Wang ◽  
Yue Sun ◽  
Mo Zhou ◽  
Naiqian Guan ◽  
Yuwen Wang ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Mixed Forest ◽  
Growing Season ◽  
Total Biomass ◽  
Herb Layer ◽  
Simpson Index ◽  
Thinning Intensity ◽  
Ground Biomass ◽  
Below Ground ◽  
Understory Herb

Abstract Background Herbs are an important part of the forest ecosystem, and their diversity and biomass can reflect the restoration of vegetation after forest thinning disturbances. Based on the near-mature secondary coniferous and broad-leaved mixed forest in Jilin Province Forestry Experimental Zone, this study analyzed seasonal changes of species diversity and biomass of the understory herb layer after different intensities of thinning. Results The results showed that although the composition of herbaceous species and the ranking of importance values were affected by thinning intensity, they were mainly determined by seasonal changes. Across the entire growing season, the species with the highest importance values in thinning treatments included Carex pilosa, Aegopodium alpestre, Meehania urticifolia, and Filipendula palmata, which dominated the herb layer of the coniferous and broad-leaved mixed forest. The number of species, Margalef index, Shannon-Wiener index and Simpson index all had their highest values in May, and gradually decreased with months. Pielou index was roughly inverted “N” throughout the growing season. Thinning did not increase the species diversity. Thinning can promote the total biomass, above- and below-ground biomass. The number of plants per unit area and coverage were related to the total biomass, above- and below-ground biomass. The average height had a significantly positive correlation with herb biomass in May but not in July. However, it exerted a significantly negative correlation with herb biomass in September. The biomass in the same month increased with increasing thinning intensity. Total herb biomass, above- and below-ground biomass showed positive correlations with Shannon-Winner index, Simpson index and Pielou evenness index in May. Conclusions Thinning mainly changed the light environment in the forest, which would improve the plant diversity and biomass of herb layer in a short time. And different thinning intensity had different effects on the diversity of understory herb layer. The findings provide theoretical basis and reference for reasonable thinning and tending in coniferous and broad-leaved mixed forests.

scholarly journals Different Roles of Top-Down and Bottom-Up Processes in the Distribution of Size-Fractionated Phytoplankton in Gwangyang Bay

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1682
Author(s):  
Yoonja Kang ◽  
Yeongji Oh
Keyword(s):  
Nutrient Availability ◽  
Fast Response ◽  
Nutrient Addition ◽  
The Other ◽  
Zooplankton Grazing ◽  
Top Down ◽  
Bottom Up ◽  
Phytoplankton Distribution ◽  
Summer Bloom ◽  
Gwangyang Bay

The interactive roles of zooplankton grazing (top-down) and nutrient (bottom-up) processes on phytoplankton distribution in a temperate estuary were investigated via dilution and nutrient addition experiments. The responses of size-fractionated phytoplankton and major phytoplankton groups, as determined by flow cytometry, were examined in association with zooplankton grazing and nutrient availability. The summer bloom was attributed to nanoplankton, and microplankton was largely responsible for the winter bloom, whereas the picoplankton biomass was relatively consistent throughout the sampling periods, except for the fall. The nutrient addition experiments illustrated that nanoplankton responded more quickly to phosphate than the other groups in the summer, whereas microplankton had a faster response to most nutrients in the winter. The dilution experiments ascribed that the grazing mortality rates of eukaryotes were low compared to those of the other groups, whereas autotrophic cyanobacteria were more palatable to zooplankton than cryptophytes and eukaryotes. Our experimental results indicate that efficient escape from zooplankton grazing and fast response to nutrient availability synergistically caused the microplankton to bloom in the winter, whereas the bottom-up process (i.e., the phosphate effect) largely governed the nanoplankton bloom in the summer.

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